Question 337·Easy·Math

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For what value of $x$ does

3(x - 4) = 2x + 5

A linear equation has an unknown raised only to the first power, even if that unknown appears on both sides. If a number sits outside parentheses, multiply it by every term inside before solving. Then use a Desmos regression to find the value that makes both sides equal. Missing a negative term during distribution changes the equation.

Hints

Hint 1
The distributive property says the number outside parentheses multiplies every term inside. The $3$ reaches both $x$ and $-4$ . What is $3(-4)$ ?
Hint 2
A solution makes the two sides equal. In Desmos, replace $x$ with $x_1$ and $=$ with $\sim$ to find that input. What value appears under PARAMETERS?

Step-by-step

Distribute, then solve in Desmos
Step 1
Distribute the 3
Use the distributive property: the $3$ multiplies both terms inside the parentheses. In particular, $3(-4)=-12$ , so rewrite the equation:
$3x-12=2x+5$
Step 2
Find the value that makes both sides equal
The rewritten equation is $3x-12=2x+5$ . Type $3x_1-12\sim 2x_1+5$ in Desmos. This regression uses $x_1$ for the unknown and $\sim$ to find when the two sides are equal. Under PARAMETERS, Desmos shows $x_1=17$ , so the value of $x$ is $17$ . Choice C.

Question 337·Easy·Math

Strategy

Hints

Step-by-step

Lessons that teach this

Study Hints

Strategy

Hints

Step-by-step

Lessons that teach this